/**
 * JWT
 * https://docs.topperpay.com/widgets/
 * @see https://notes.salrahman.com/generate-es256-es384-es512-private-keys/
 * Algorithm	Curve
 * ES256	prime256v1
 * ES384	secp384r1
 * ES512	secp521r1
 */
export declare function generateES256Keypairs(passphrase: string): import("crypto").KeyPairSyncResult<string, string>;